1. State Key Discipline Laboratory of Wide Band Gap Semiconductor TecchnologyShaanxi Joint Key Laboratory of GrapheneSchool of MicroelectronicsXidian University 2 South Taibai Road Xi'an 710071 China
2. School of Physical Science and TechnologyShanghai Tech University 100 Haike Road Shanghai 201210 China
3. Centre for Spintronics and Quantum SystemState Key Laboratory for Mechanical Behavior of MaterialsSchool of Materials Science and EngineeringXi'an Jiaotong University Xi'an Shaanxi 710049 China
4. Key Laboratory of Applied Surface and Colloid ChemistryNational Ministry of EducationShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal University Xi'an 710119 China